Telegraph system



J. H. BELL. TELEGRAPH SYSTEM.

1,337,748. Patented Apr. 20, 1920.

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- UNITED sTA Es PATENT OFFICE.

JOHN H. BELL, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR T WESTERN ELECTRICCOMPANY, IN GORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Application filed November 21, 1917.

To all whom it may concern:

Be it known that I, JOHN H. BELL, a citizen of the'United States,residing at South Orange, in the county of Essex and- State of NewJersey, have invented certain new and useful Improvements in TelegraphSystems, of which the following is a full, clear, concise, and exactdescription.

This invention relates to telegraph systems and more particularly tosubmarine telegraphy.

The principal object of this invention is to provide an improvedorganization of apparatus for overcoming the phenomenon known aswanderin zero experienced in line conductors havmg high electrostaticcapacity.

The invention is more particularly ap plicable to systems in which anuninterrupted alternating current, preferably of sine-wave form, isimpressed on the cable, the message impulses being in the form ofaugmented half waves of either positive or negative polarity, z. 6.,half waves of increased amplitude.

In such systems when two or more augmented half waves of positivepolarity, for example, are separated by negative half waves of normalamplitude, there results a cumulative charge on the cable whichmanifests itself as an apparent shifting of the zero line, so that inthe case in question the current at the receiving end of the cableinstead of alternating from positive to negative might appear simply asa fiuctuating positive current.

With some forms of receiving devices, such, for example, as the siphonrecorder, it is possible to read such distorted signals without muchdifiiculty.

IVhen, however, an automatic recording of the signals is desired, as inprinting telegraphy, it becomes necessary to employ marginal receivingdevices to differentiate between augmented half waves and normal halfwaves. In such cases it follows that if the distortion of signals abovementioned is not corrected or compensated for in some way, the operationof such marginal device 'may be seriously interfered with.

The present-invention provides a receiving system which automaticallycompensates for suchdistortion. The arrangement employs two receiverrelays or impulse receiving means with a local circuit under theSpecification of Letters Patent.

Patented. Apr. 20, 1920.

Serial No. 203,083.

control of each to accelerate the action of the other.

The arrangement chosen as a preferred embodiment of this invention isillustrated diagrammatically in the accompanying drawing, in which onlyso much of a telegraphic receiving equipment is shown as will benecessary to a clear understanding of the system.

The drawing, Figure 1, is a schematic circuit arrangement of a telegraphreceiver equipment. Figs. 2 and 3 each similarly illustrate respectivealternate arrangements of the receiving equipment shown in Fig. 1.

In describing the operation of this system attention will first bedirected to the drawing, Fig. 1. A telegraph lin'e indicated by'.

the reference numeral 1 is connected serially through the line windings3 and 23 of polarized relays 2 and 22, respectively, and an artificialline AL to earth. For the relay 2 a second circuit may be traced from asource of current 8, an'impedance coil 9, a local winding 4 of thisrelay, a resistance unit 10, thence through a condenser 11 to earth. Ina similar manner a circuit extends from the battery 8 through animpedance coil 29, a local winding 24 of the relay 22, a resistance unit30, thence through a condenser 31 to earth. The armatures 5 and 25 ofthe relays 2 and 22 respectively, are normally biased to the position inwhich they are shown, thereby establishing a first circuit which may betraced from a source of current 40, through the left-hand winding of arelay 41, and the contacts 6 of the relay 2 to earth, and anothersimilar circuit from the source 40, the right-hand winding of the relay41 and the contacts 26 of the relay 22 to earth. Currents through thecircuits just traced act differentially in the relay 4:1 which,therefore, remains inert.

For convenience of description it will be considered that under animpulse of positive current from the line 1 the armature 5 of the relay2 will move to close its contacts 7 while the same impulse will notaffect the inverse action. whereby the armature of the relay 22 wouldmove to close its contacts 27, while the armature of the relay 2 wouldhold more firmly to its contacts 6. The relay 41 controls, (by means notshown) any suitable signal receiving device, as a tape recorder orprinting telegraph receiver, and is energized at any moment that eitherthe contacts 6 of the relay 2 or the contacts 26 of the relay 22 areopen. Biasing of the relay armatures 5 and 25 may be effected by meansof suitable retractile springs, or the energy of the sensitizin orpolarizing magneti'sm may be employe for this purpose by adjustmentswhereby a greater gap space would be present in the magnetic circuit atone side of the armature, or other convenient design of the relay aswill be readily understood by those skilled in the art. In order thatthe drawing would not be unnecessarily complex polarizing means for therelays 2 and 22 have not been shown.

Referring now to the local circuits of the relays, the condenser llischarged over the circuit already traced when the contacts 27 of therelay 22 are separated, and discharged to the earth connection extendingfrom the relay armature when the contacts 27 are closed. In a likemanner separation of the contacts 7 of the relay 2 permits the condenser31 to charge and the closing of these contacts discharges thiscondenser. The direction relation between the line and local winding ofeach polarized relay is such that the charging and discharging of therespective condenser will always be accumulativewith half-Wave currentsfrom the line circuit 1. It will, therefore, be obvious that an impulseof positive current from the line 1, on moving the armature of the relay2 to close its contacts 7, will thereby permit the condenser 31 todischarge through the winding 24 of the relay 22 in a direction toassist the positive impulse through the line winding 23 in retaining thearmature of this relay on its contacts 26. In phase with and immediatelyfollowing the impulse of negative current from the line 1, retraction ofthe armature of the relay 2 will be accelerated thereby, while thearmature of the relay 22 will move to close its contacts 27. Inconnection with these operations, at the instant the contacts 7 of therelay 2 separate, charging of the condenser 31 takes place through thewinding 24 of the relay 22 to assist the negative current in the winding23 in moving the armature 25 to close its contacts 27. On the instantthe contacts 27 close, the condenser 11 discharges through the winding 4of the relay 2, thereby assisting the remainmg portion of the negativeimpulses in the winding 3 in bringing the armature of this relay tofirmly close its contact 6.

The relays 2 and 22 should be of suitable designv or adjusted in such amanner that although they will remain inert. in the position shown,under currents of a predeter- .mined strength they will neverthelessrespond to currents of an incremented or max- .imum strength. Such rangelimits of adjustments should be made on the basis of the accumulativeaction of both the line current and the static or condenser current .ineach relay as already described' It will therefore, be clear, thatalthough these polar relays will remain inert under alternating currentsof a minimum strength, they Wlll respectively respond to alternations orhalfwave currents of a maximum strength.

In the further description of this system let it be assumed that thearmature of each polar relay is biased by means of a suitable adjustmentof the magnetism employed for establishing their polarization. It willbe mentioned that in the drawing biasing sprin s have been shown merelyas a matter 0 convenience in order that the system may be more readilyunderstood. If, now, two half waves of positive polarity and of maximumstrength from the line 1 are separated by a negative half wave ofminimum strength the relay 2 will respond to the two positivealternations and each time its contacts 6disconnect the left-handwinding of the relay 41 in response thereto, the current from the source40 already present in the right-hand winding of the latter relay, asalready described, will effect the operation of this relay. Now,assuming that the third alternation of positive sign and maximumstrength is followed by a negative alternation of maximum strength thelatter impulse would not rise to its prescribed volume, due to thepreponderance of the positive charge retained by the cable. Since thearmatures of the polarized relays when operating will move relatively inphase with the wave currents, at the instant the assumed negativealternation begins, the armature of the positive responding relay 2 willstart on its return trip, thereby separating the contacts 7. Thereuponthe condenser 31 receives a charge from the battery 8 and this currentthrough the windings 2 L acts cumulatively with the negative impulse inthe line winding 23 of the relay 22 to move the. armature 25 to closeits contacts 27.

Although the distortion may have reduced the negative impulse to astrength below a value alone suflicient to operate the reray 22, theaugmenting action of the condenser discharge creates the additionalenergy required to move the relay armature. Separation of the contacts26 of the relay 22 disconnects the right-hand winding of the relay 41and at the instant the contacts 27 of the polar relay close, the circuitis completed to discharge the condenser 11, the current of which actsthrough the winding 4 to assist the negative alternation present in theline winding3 in quickly and firmly closing the contacts 6 of thisrelay, following which current from the battery 40 travthe units 9 and29 and also the effect of the resistance units 10 and 30 is to lag orretard the currents set up by the condensers 11 and 31, respectively, inorder that the currents through the relay windings 4 and .24 will bebrought more nearly in phase with current pulsations through the linewindings 3 and 23.

From the foregoing description it will be clear that contacts controlledby the relay 2 control the action of currents through operating windingson the relay 22 and in a like but converse manner the same control isefiective from, the relay 22 to the relay 2.

Referring to the drawing (Fig. 2) similar characters of reference havebeen employed in this drawing to indicate parts that are like or thatcorrespond to parts in the figure already described. This alternatearrangement differs from the first prlncipally through the fact that theconnections to the contact stops of the relays 2 and 22 are reversed. Bythis change, on the instant the normal contacts (6, 26) of either relayopen, the condenser associated with the local winding of the oppositerelay is charged, thereby affecting that relay in a manner as alreadydescribed. At the instant the normal contacts of either polar relayclose, the condenser of the opposite relay is discharged through itsassociated winding. It may also be pointed out that the translatingrelay 41 is normally on open circuit,the contact '7 of the relay 2completes an energizing circuit through itsleft-hand winding in responseto an incremented half wave of positive current from the line 1, while anegative impulse of similar strength from the line will operate therelay 22, whereby its contacts 27 establish energizing current throughthe right-hand winding of the relay 41.

In considering the alternate arrangement shown in Fig. 3, an incrementedhalf wave of positive current from the line 1 will move.

the armature of the relay2 to close its contact 7, thereby establishingthe source of cur rent 40 through the winding of a receiver controlrelay 42 and a resistance unit 43 to earth. In addition to operating therelay 42, current also traverses a resistance unit to a connectionintermediate the two spool sections forming the local circuit windings24 of the relay 22. This current in branching acts through theright-hand coil to charge the condenser 31 and com pletes circuitthrough the left-hand coil and the resistance unit 30 to earth. Thesteady current through the left-hand coil of the relay 22 is of suchstrength that it will exert only suflicient pressure on the armature 25to approximately relieve the biasing force by which it is held in theposition shown. If now the first alternation of incremented positivecurrent from the line 1 is followed by an incremented inversealternation the latter current will act to move the armature of eachrelay to the left. 'On the instant the contacts 7 of the relay 2separate, the condenser 31 discharges through the winding 24 of therelay 22 and the resistance 30 to earth, thereby augmenting the negativealternation from the line 1 in moving the armature 25 to close itscontacts 27. Through the latter contacts the battery 40 is connectedthrough the winding of a second receiver control relay 45 and aresistance unit 46 to earth. It will be noted that the contacts of thelatter relay are connected in parallel with the contacts of the relay42. Therefore, these relays serve to control the same receiving circuits(not shown). Closure of the contacts 27 of the relay 22 also includescurrent from the battery 40 through a resistance unit 47 to charge thecondenser 11 and also to maintain a steady current through the left-handcoil of the winding 4 of the relay 2 and a resistance unit 10 to earth.In case a third alternation from the line 1 is of incremented value, itspolarity being positive, at the in stant the contacts 27 separate as thearmature of the relay 22 starts on itsreturn or restoring trip, thecondenser 11 will discharge through the winding 4 and resistance unit 10to earth, thereby augmenting the action of the line impulse in movingthe armature of the relay 2 to close its contacts 7. The assistingaction is reciprocal with respect to the two line relays 2 and 22 and itmay be mentioned that at the instant the condenser 11 or 31 receives acharge, the charging current acts differentially through the right-handcoil section of the winding 4 or 24, respectively, with respect to thesteady current through the left-hand portion of this winding.

From the foregoing description it will be clear that in addition tocontrolling the translation of impulses from a line circuit to localreceiving apparatus, each of the line relays controls circuits on theother relay, respectively, to render it more sensitive to impulses fromthe line to which it should respond.

What is claimed is:

1. In a telegraph receiver, a first and a second impulse receivingmeans, and means controlled by each one of said impulse receiving meansfor accelerating the response to impulses respectively by the otherreceivmg means.

23 In a telegraph receiver, a first and a second rela respectivelresponsive in the reception 0 positive an negative impulses, and acondenser worked by each relay to respectively aid the operation of theother relay.

3. In a telegraph receiver, a first and a predetermined characteristics,and means associated with each of said devices and respectivelycontrolled by another one of said devices to render it effective toaccelerate the response of the-respectively associated dev1ce.

- 5. In a telegraph receiver, a first and a second relay respectivelyresponsive to currents of opposite polarities, signal translating meanscontrolled by said relays, a condenser controlled by each relay foraccelerating respectively the response of the other means forcontrolling the electrical time constants of said condenser'circuits.

6. In a telegraph receiver, a first and a second line relay respectivelyresponsive to relay, and

currents of o posite polarities, a first and a second win ing for eachof said relays, a condenser included with the second winding of each ofsaid relays, contacts for each relay to control the circuits of a signaltranslator, said first windin of each relay arranged for the reception0% impulses from a line circuit, the second winding of each relayrespectively controlled by said contacts of the other relay to establishcurrent therein which will aid an impulse of current throulgh the firstwinding of the same relay.

7. na telegraph receiver, a first and a second compound wound relayrespectively responsive to current of predetermined characteristics, oneWinding on each relay arranged for the reception of impulses from a linecircuit, contacts for each relay to control a signal translator circuit,a condenser and an impedance coil included with the other winding ofeach relay, a source of current, said contacts of each relay arranged tocharge and discharge the condenser of the other relay respectively inorder that the action of a signaling impulse through the first windingwill be augmented by the electrostatic current through the other wind-%n witness whereof, I hereunto subscribe my namethis 16th day ofNovember, A. D.

JOHN H. BELL.

